Continuous-surface blow-down system for boilers



April 29, 1930. D. R, YARNALL 1,756,620

CONTINUOUS SURFACE BLOW DOWN SYSTEM FOR BOILERS Filed March 5, 1920 Patented Apr. 29, 1930 vireo sures DAVID ROBERT YARNALL, OF PHILADELPHIA, PENNSYLVANIA CONTINUOUS-SURFACE BLOW-DOW'N SYSTEM FOR BOILERS Application filed March 5,

My invention relates to boiler cleaners op erating upon the closed circuit skimmer principle for removing sediment from the water handled by means of circulation of the boiler water through a precipitator induced by a temperature differential in the connection from the boiler to the precipitator.

The purpose of my invention is to produce a positive circulation in the skimmer system because of the difference in temperature be tween the water in the boiler and the water in a precipitator placed below the level of the water in the boiler, wholly independent of boiler inlet feed.

A further purpose is to insert a cooler in the closed skimmer system between the boiler and the precipitator.

A further purpose is .to provide circulating means for theskimming system which are capable of regulation or variation in the volume of flow and the flow velocity without regard to the conditions of boiler feed.

Further purposes of my invention will appear in the specification and in the claims.

.I have preferred to illustrate one form only, by which the circulation may be secured, among the many means available, selecting a form which is practical, efficient,

reliable and inexpensive, and which at the same time well illustrates the principles of my invention.

Figure 1 is'a broken side elevation, partly in section, of one form of my invention.

Figure 1 is a broken side elevation corresponding to Figure 1 but showing a modified form.

Figure 2 is a side elevation, partly invertical central section, of a gravity precipitator used in a skimmer system. I l t Figure 3 is 'a vertical section showing an injector by which the circulation is improved. In the drawings similar numerals indicate like parts.

Skimmer systems with gravity sediment precipitator have long been opera'ted'with circulation induced by the difierences in temperature at the inlet and outlet points, and the corresponding difference in weight 0 of equal volumes of water at the two tempera- 1920. Serial No. 363,469.

tures. These have operated splendidly in some installations and in others the operation has been indifferent and uncertain because of low effective head or for a variety of other possible reasons.

One investigator has proposed to remedy this by causing the boiler feed inlet to induce fluid flow through the precipitator. This is objectionable because it makes the circulation dependent upon the insertion of feed water and restricts the point of insertion of the feed water to the return connection from the precipitator. It injects an outside connection requiring a large liquid volume to; make it operate and has a very slow speed.

My invention is intended to make the circulation standard, practically independent of the diiferences in temperature of the normal precipitator inlet and return connections and free from interference by fluid friction" and the other accidental or casual causes of obstruction toifiow which affect the less distinct and positive gravity flow, and without the necessity of introducing a pump having moving parts. I use as a fluid inducing means steam from the boiler itself, which has a high temperature and a high inducing velocity but is very low in liquid volume.

I recognize that the character of device by Y which the flow is increased or standardized may be greatly varied while obtaining substantially the same efiect. However, as illustration of'all of the possible forms is impracticable as well as unnecessary I have il- 7 lustrated one distinct type only, in the form of an injector nozzle. v v

My invention is of course independent of the type of injector used, and could be used with any other suitable means ofinducing flow, whether employing steam as 'apropellant, or utilizing water under pressure or any other suitable energy source.

In Figure 1 I haveshown a conventional boiler 10 having hot 'air pipes 11 and containing 2; Chase skimmer system illustrated in the application of Lyle G. Chase, Serial No. 254,367, filed September 16, 1918 andin which the longitudinally extending pipe 12 is connected with upwardly extending tubularinlet pipes 13 having wedge-shaped side openings at 14: alternating in direction, to-

ward the observer and toward the adjacent pipes.

This skimmer system is connected through pipe 15, suitably valved as at 16, with aprecipitator l7 ofwhich one form is shown in Figure 2, and through the precipitator by pipes.18,18', 18 also suitably valved as at 19, with the bottom of the boiler at 20.

For the satisfactory operation of the closed skimming, system according to my invention it is necessary that the precipitator ciplitator.

be located below the level of'the water in the boiler. There is then a downwardly directed flow from the skimmerconnectionto the prehe water is cooled between the boiler outlet and the precipitator by a radiator construction illustrated typically at 21 so as to magnify the temperature contrast between the water entering the precipitator a'IlClthe water in the bottom of theboiler.

The location ofthe cooler 21 in relation to the level of the water in the boiler is not important. Since the prec'ipitator is located below the boiler water level,,the line from the skimmer-to theprecipitator, and including the cooler, will of course include a vertical leg which will assist the circulation.v

The precipitator is shown ashaving inlet 211122, outlet at 23, and intermediate vertical partition 24: and bell. 25, about which sediment settles into the. bottom 26. The forms '.of skimmer system'andsprecipitator are not involved in the present invention, but may both be considered for the purposes of this application as conventional forms.

Inorder to improve the circulation so as to increase the flow of fluid through the precipitator and give a larger volume of water per unit of time from which thesolid matter in suspension may be removed by the precipitator, I apply an accelerator shown in F i g. ure v1 as an injector 27 of which oneform is shown in detail in Figure 3., Here steam from the boiler is applied through a suitable nozzle 28, surrounded by water at29 with the result that water flow is induced downwardly through thepipe 18, causing circulation of the water in the system upon the well known injector principles. Theiniector should be located abovethe level of; the water in the boiler. Hand valve-30 and check valve 31 are shown forcontrollingthe steam.

The invention isnot inv the injector itself wh ch forpresent purposes maybe regarded as conventional- .only. It depends for itssuc- "cessupon the kinetic energy of the steamflow more than offsetting the tendency to reverse flow. caused'by the heat units absorbed from the-steam.

This steam means is capable of easy adjustment to vary the speed of flow by changng t ezquantityoi steam; introduced; is simple, is easily apphed,afiords a minimum of in .the precipitator.

steam condensation on account of the high temperature of the water handled, and is-efspeeds of flow over measured times and de termini'ng for each the quantity of suspended matter removed from the, circulatory system structure of Figurev 1 is In Figure 1 the the modified to place the injector at about level of the precipitator outlet. ,7

In Figure 1 Ihave shown the fluid driving means as located between the precipitator and the bottom of the boiler. However, I wish to clearlyindicate thatthe location of this means is not to be restricted, and that the injector may be'located in the closed. system on either slde of the precipitator Otof the cooler, provided the piping is rearranged to place the injector in a position such that it will function properly.

It is my purpose, in view of mydisclosure herein, to cover all combinations of driving means, cooling apparatus, and precipitatorin a closed skimming system for a steam boiler which may come within the claims or within the spirit and scope of my invention.

Having thus described ny invention, what Iclaim as new and'desire to secure by Letters Patent is 1. In a steam generating system utilizing; a boiler, a skimmer, an artificialcooler, a

precipitator, connections through the cooler from the skimmer to the precipitator, up- 7 wardjly extending-return connections from the precipitator from apoint below to a point above the level of the water in theboiler, a

connection from these return connections extending from. the point above the water level in the boiler to-the interior of the boiler and a steam jet injector in "said 7 last named connection located at a point abovethe level of the water in the boiler and adapted to accelerate thespeed of the waterinthe last connection.

2. In a steam generatingsystemutilizing a boiler, a skimmer, a precipitator, located below the water level in the boiler, connections extending down from the skimmer ,to the precipitator, a cooler.in the connections, return connections from the precipitator-tothe boiler. and ste m circu ating means in the return. connections located above the-level of the water in the boiler.

3. A skimmer system for-a boiler, comprising skimmeradaptecl to. ie-plac in he boiler, a. precipitator below the Water level in the boiler and connections extending down from the skimmer to the precipitator, return connections from the precipitator to the boiler, a cooler in the connections from the skimmer to the precipitator and drive means for positively moving the Water in the connec tions to increase the speed of circulation.

DAVID ROBERT YARNALL. 

